The Centers for Disease Control and Prevention (CDC) calls measles, a virus that lives in the nose and throat, the “most deadly of all childhood rash/fever illnesses”. About 90% of those who are not immune will become infected if they come close to an infected person, according to the CDC. An estimated 20 million people worldwide contract measles each year. In the US, the CDC typically expects only 220 cases. Last year there were 644, a nearly two-decade high. Yes, this was due to a marked drop in immunization rates in certain parts of the country.

In discussing the recent measles outbreak, one of the most common responses I received was “So? What’s measles anyway?” It has been that long since measles has been a problem in the United States. Let’s talk about common questions related to measles.

What causes measles? The medical term for measles is rubeola, and it’s caused by a virus.

What are the symptoms I’d see? To the layperson, measles most often presents as a full body rash with cold/flu-like symptoms, such as a fever, cough and runny nose. Your doctor is also looking for red eyes (conjunctivitis) and small reddish spots inside the mouth (known as Koplik’s spots).

Is measles contagious? It’s highly contagious to those not immunized. According to the Center for Disease Control and Prevention, 90% of those not immunized will contract measles if exposed to someone with it.

How is it spread? It’s spread through the air. This means sneezing, coughing and kissing.

Why don’t I ever see measles? Measles has been contained in the U.S. since the introduction of the measles vaccine over 50 years ago. It is amazing to think that there are still 20 million cases still occurring around the world annually.

How is measles prevented? Immunization! The immunization is approximately 99% effective in preventing infection in the face of exposure. Infants are generally protected from measles for 6 months after birth due to immunity passed on from their immunized mothers. For most others, the measles vaccine is part of the measles-mumps-rubella immunization (MMR) or measles-mumps-rubella-varicella immunization (MMRV) given at 12 to 15 months of age and again at 4 to 6 years of age. Additional considerations exist in the face of an outbreak.

What are the side effects of the vaccine? Unless you have an underlying health condition and/or have a reduced immunity, the most common reactions include the following:

fever 6-12 days after vaccination (in about 5%-15% of those vaccinated)

an incidental (and non-allergic, non-contagious) rash. This goes away on its own and occurs in about 5% of vaccine recipients.

What’s the treatment of measles? Given that measles is a virus, there is no specific medical treatment (as is almost always the case with viruses). Supportive treatment is important and involves fluids and rest for what is expected to be a two-week period. Something like Tylenol or children’s ibuprofen can be given for fever or pain (but never give aspirin to a child).

What are the common complications? 30% of cases of measles involve complications. Complications include simpler conditions such as otitis media (those pesky ear infections), croup and diarrhea.

This all sounds pretty benign. Why not just get the disease and avoid the vaccination? Because children can die from measles. Unfortunately, measles also has more serious considerations such as pneumonia (which occurs in approximately 1 of 20 cases) and a serious brain infection called encephalitis (which occurs in approximately 1 of 1000) cases. Measles also causes pregnant women to have miscarriages, premature births or low-birth-weight babies.

How do people die from measles? Pneumonia is the complication most often causing death. For every 1,000 children who acquire measles, 1 or 2 will die.

What’s the Vitamin A connection with measles? Vitamin A has been found to decrease complications and death in those infected with measles. It should be considered, especially in those hospitalized with complications of measles or those who have compromised immune systems and acquire measles.

If I had measles as a child and get exposed to the disease again, am I in danger? No. Surviving a measles infection provides one with life-long immunity. Of course, your take home message is most of this isn’t a consideration if you simply get immunized.